Electrolytic apparatus for cleaning strip



Dec. 26, 1950 A. TEPLITZ 2,535,966

ELECTROLYTIC APPARATUS FOR CLEANING STRIP Filed Feb. 7, 1947 2 Sheets- Sheet 1 F'IE-1- A A I (9 g 9 if I I 50 5-: :33; if

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Dec. 26, 1950. A. TEPLITZ 2,535,966

': ELECTROLYTIC APPARATUS FOR CLEANING STRIP Filed Feb. 7, 1947 2 Sheets-Sheet 2 17206725072 407E517 TEFL/T2;

A ZM 0% Patented Dec. 26, 1950 ELECTROLYTIC APPARATUS FOR CLEANING STRIP mafia repfl' tz; Pittsburgh, Pa. Application February '7, 1947,'Serial No. 726,995

1 This invention relates to apparatus for electrolytically cleaning metallic strip and more par ticularly to cleaning such. strip in vertical passes. Most of the electrolytic cleaning of metals in strip form is performed in horizontal passes which method possesses inherent disadvantages, chief of which are:

1. Equipment utilized requires a great deal of floor space. 2.. Clearance required between "the strip and the electrodes between which the strip passes are great in order to avoid short circuits re sulting from vertical whipping of the moving strip. ,TfhlS excessive .clearancecincreases the resistance of the electrical circuits, limits current density and lowers operating efllciency.

3.. Current density and/cleaning action are limited due to blanketing of the electrodes hi; evolved gases. l 4. Stray current lossesgdue to thearrangement of the electrical circuits. 1 z Vertical cleaning passes have been used to a slight extent, but those in use also have various disadvantages. For example, the maximum cleaning action is not obtained at all times because-of entrained gases in the electrolyte and the-type of electrical hook-up. In addition, it is difficult to vary the operation to suit variable conditions. Another disadvantage is that the currentdensity is limited becausethe gas bubbles evolved blanket the electrodesurfaces, thus in; creasing the electrical resistance and causing high voltage drops. l I

It is an object of my invention to provideuan electrolytic tank which operates uniformlyat a high eificiency. Anotherobject is to provides-means for-car rying off the gas bubbles evolved. Still another object is-to provide means for releasing the entrained gases in the electrolyte;

These and other objects will be more apparentaf-ter referring to the following specification and attached drawings, inwhich: I l Figure l is a schematic longitudinal section through the electrolytic tank; Figure 2 is a sectional view taken on the line II--II of Figure 1,; and r Figure-3 is an enlarged detail of the electrode adjusting means. ygReferring more particularlylcto the drawings, the-reference numeral 2 indicates an electrolytic tank having a chamber 4 in the lower pantthere of and a-pair or restricted passageways 6 leading upwardly from said chamber-tome top at the tank. Plates 8 forma substantially hori- 4 Claims. (Cl. ;204-206) 1 H 2 zonta'l wall separating the tank 2 into the lower chamber 4 and an upper chamber Q. Mounted in each of the restricted passageways '5 is a pair of electrodes in, each of which is mounted for movement toward the other as shown in detail in Figure 3. The top of the wall of the passageway *3 is bent outwardly to provide a horizontal flange i having a threaded hole i5 therein communicating with the threaded opening in a nut it welded to the under side of the flange l2. The electrodes it are removable and the upper part thereof is bent outwardly to provide a horizontal flange 18'. A slot 20 .is provided in this flange "for receiving a stud bolt 22 which is threaded downwardly through the hole M in the .nut id to hold the electrode H3 in place. A threaded hole 24 is provided in the electrode ill some distan e from its top and has a nut 26 positioned thereover which is welded to the elec trode. A hole 28 is provided in the wall of passages-sly 5 and a hole 36 in axial alignment therewith is provided in the wall of the tank 2. A bracket 32 is welded or otherwise fastened to the outside of tank 2 and is provided with an opening 3:! which is .in alignment with openings 28 and SEE. A threaded stud bolt 36 passes through these aligned openings and is threaded into the nut 26 and hole 24. Nuts 38 and 40 are screwed on thebolt 3!: between the bracket 32 and the wall of the tank 2 with a washer 52 being provided betweenthe nut 25} and the wall of tank 2 to prevent leakage of electrolyte from the tank. It will be apparent that the electrode IID can be moved toward and away from the center of the passageway B by changing the position. of nuts 38 and 40.

' Fastened to the outside of passageways 6 and to thesides of tank 2 are cascade plates 44. An entry conductor roll is mounted above one of the passageways B and a delivery conductor roll 48 is mounted above the other passageway 5. A rubber covered sink roll 59 is positioned in the chamber 4,, which is provided with .an inlet 52 for the electrolyte. A hood 15 i surrounds the 4 rolls 45 and 4B in the top .of the tank and collects the *fumes from the cleaning operation. A cone dult 58 leads from the hood 46 to an exa-hust fan (not shown). The strip S enters the tank 2 over the entry conductor roll 46 and passes downwardly between one pair of electrode liners Ill which are arranged so that the clearance between the electrodes and the strip will give the most effective cleaning action. The strip then passes under the sink roll upwardly between the other pair of electrode liners 1-0 and over the exit roll 48, the second pair of electrode liners also being arranged so that the clearance between the electrodes and the strip will give the most efiective cleaning action. Hold down rolls 60 are provided at each conductor roll to insure good contact between the rolls and the strip with the hold down roll for the exit conductor roll 48 also preventing electrolyte drag out.

As shown in Figure 2, the shaft 62 of the sink roll 56 passes through the shaft seals 54 at each end of the tank, the shaft seals being insulated from the tank 2 by means of insulation 66. The shaft 62' is mounted for rotation on bearings 68.

The electrolyte is circulated by means of a pump ill which delivers it from a reservoir 12 to the chamber 4 through the opening 52. The

electrolyte passes upwardly through. the restrict- 4 action is double that obtained when the polarity of the strip is positive.

While one embodiment of my invention has been shown and described, it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. Electrolytic cleaning apparatus comprising a vertical tank, a, pair of conductor rolls over which a strip passes into and out of the tank, a

' sink roll at the bottom of the tank around which ed passageways t and over the surface of the I strip S at a high velocity due to the restriction of the passageways, thus carrying the evolved gases out of the electrically active zone and pre-' venting blanketing, of the electrode by these gases. Deflector plates 74 at the top of the tank confine the electrolyte within the tank. The electrolyte solution then flows over the top of the passageways ii and cascades downwardly over the plates 36, which aid in releasing the entrained gases in the electrolyte. The electrolyte leaves the tank through conduits 16 which lead to the reservoir l2. The reservoir 72 is preferably provided with means for cleaning and conditioning the electrolyte.

The electrical arrangement for supplying current to the system consists of two generators l8 and 88 having identical characteristics and which are driven from a common motor 82. The negative terminal of generator 18 is connected to the roll 55 and the negative terminal of generator 80 is connected to the roll d8. The positive terminals of generators l8 and 3E! are connected through a common lead 3 2 to the tank 2. By this arrangement any small stray currents in the tank do useful work and there are three possible circuits for the current:

1. From the generator 18 to the tank 2 and anodes Ell, through the electrolyte to the strip S, to the conductor roll and back to the generator l8.

From the generator 80 to the tank 2 and anodes 58, through the electrolyte to the strip S, to the conductor roll 38 and back to the generator 8i].

3. From the generator 13 to the generator 80, to the conductor roll 48, through the strip S, to the conductor roll 56 and back to the generator 18.

However, no current will flow through the third circuit since the voltage of generators l8 and 80 are equal and opposite. Therefore, all the current flowing must pass through the strip S into the electrolyte and in so doing evolve gas, which evolution constitutes the cleaning action. Thus maximum efficiency is obtained and any need for internal insulation of the tank or its component parts is eliminated. However, the tank and its external attachments should be insulated from their supporting structures since the strip being cleaned will normally be grounded by contact with various machines and if the tank is grounded, a current loss will occur.

In the arrangement shown, the strip is of negative polarity. This is preferable since two volumes of hydrogen are evolved from the negative electrode for each volume of oxygen evolved from the positive electrode. Thus, the cleaning the strippasses, a chamber in the bottom of said tank containing said sink roll, a pair of restricted passageways in said tank leading upwardly from said chamber, said passageways forming the only outlets from said chamber, a pair of electrodes in each of said passageways, said strip passing downwardly between one of said pairs of electrodes and upwardly between the second of said pairs, means for introducing the electrolyte into the chamber and causing it to flow upwardly in each passageway, cascade platesabove said chambers and adjacent said passageways over which the electrolyte flows after passing between the electrodes to release gases entrained therein, and means below said cascade plates for returning the electrolyte to the bottom of the tank.

2. Electrolytic cleaning apparatus comprising a vertical tank, a pair of conductor rolls over which a strippasses into and'out of the tank, a' sink roll at the bottom of the tank around which the strip passes, a chamber in the bottom of said tank containing said sink roll, a pair of restricted passageways in said tank leading upwardly from said chamber, said passageways forming the only outlets from said chamber, a pair of electrodes in each of said passageways, said strip passing downwardly between one of said pairs of electrodes and upwardly'between' the second of said pairs, means for introducing the 'el'ectrolate into the chamber and causing it to flow upwardly in each passageway, deflector plates above the electrodes between which the strip passes, cascade plates above said chani-" ber and adjacent said passageways over which the electrolyte flows after passing between the electrodes to release gases entrained therein, and

means below said cascade plates for returning the electrolyte to the bottom of the tank.

3. Electrolytic cleaning apparatus comprising a vertical tank, a pair of conductor rolls over which a strip passes into and out of the tank. a sink roll at the bottom of the tank around which the strip passes, a chamber in the bottom of said tank containing said sink roll, a pair of restricted passageways in said tank leading upwardly from said chamber, said passageways forming the only outlets from said chamber, a pair of electrodes in each of said passageways, said strip passing downwardly between one of said pairs of electrodes and upwardly between the second of said pairs, a second chamber above said first named chamber adjacent said passage ways for receiving'electrolyte as it leaves said passageways, cascade plates in said second cham ber over which the electrolyte passes, and means for returning the electrolyte from the bottom of the second chamber to the bottom of the tank.

5. Electrolyticcleaning apparatus comprising a vertical tank, substantially horizontal wall separating said tank into upper and lower cham-j bers, a pair of conductor rolls adjacent the top of the tank over which a strip passes into and l 5 out of the tank, a sink roll in the lower chamber around which the strip passes. a pair or restricted passageways in said upper chamber leading upwardly from said horizontal wall to a point adjacent the top of the tank and openinginto said lower chamber, a pair of electrodes in each of said passageways, said strip passing downwardly between one of said pairs of electrodes and .upwardly between the second of said pairs, an inlet into the lower chamber, an outlet from the upper chamber adjacent the bottom thereof, and means for circulating the electrolyte from said outlet to said inlet and through said passageways to said upper chamber.

ALFRED TEPLITZ.

REFERENCES CITED The following references are of record in the file of this patent:

Number Number 6 UNITED STATES PATENTS Name Date Mace Jan. 2, 1917 Perkins Jan. 10, 1922 Mason Apr. 19, 1927 Taylorson Mar. 2, 1943 Allen Apr. 20, 1943 Grace July 30, 1946 Martz Dec. 2, 1947 FOREIGN PATENTS Country Date Great Britain of 1907 Great Britain of 1909 Switzerland Aug. 5, 1901 Germany Jan. 5, 1939 

